Fatigue Scattering Analytics of SS 316L Processed by Laser Fusion - Defect Dataset
Description
Paper Abstract: Laser powder bed fusion (LPBF) is a promising technology for manufacturing of high-strength parts with complex geometries. However, LPBF parts are notorious for generating geometrical defects (e.g., porosity) which make it challenging to merit applications involving fatigue due to the porosity-induced fatigue scattering. LPBF fatigue data and scattering studies in the literature are sparse but also inconsistent. This raises questions about the statistical significance of measured fatigue life distributions. There are also possible over or underpredictions of endurance limits, leading to unsafe designs or loss of advantages by being overconservative. This paper outlines a robust fatigue testing method for constructing S-N curves of LPBFed SS 316L to gain insights into the scattering nature of the fatigue performance at different stress amplitudes. Two different runout criteria (1×107 and 2×107 cycles) are also applied to investigate any fatigue limit underestimation and scattering about the knee point. The endurance limit is about 300 MPa for the selected process parameters and the resulting defect size distribution. The defect size-based model underpredicts the endurance limit by about 30 MPa compared with the experimentally determined data. In addition, the experimental scattering is quantified by using 95% prediction intervals for the fatigue life, showing that high stresses result in low scattering while stresses near the knee point have large variations in fatigue life.